Asymmetries in vestibular evoked myogenic potentials in chronic stroke survivors with spastic hypertonia: Evidence for a vestibulospinal role

Derek M. Miller*, Cliff S. Klein, Nina l Suresh, William Z Rymer

*Corresponding author for this work

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

Objective: Indirect evidence suggests that lateralized changes in motoneuron behavior post-stroke are potentially due to a depolarizing supraspinal drive to the motoneuron pool, but the pathways responsible are unknown. In this study, we assessed vestibular evoked myogenic potentials (VEMPs) in the neck muscles of hemispheric stroke survivors with contralesional spasticity to quantify the relative levels of vestibular drive to the spastic-paretic and contralateral motoneuron pools. Methods: VEMPs were recorded from each sternocleidomastoid muscle in chronic stroke survivors. Side-to-side differences in cVEMP amplitude were calculated and expressed as an asymmetry ratio, a proxy for the relative amount of vestibular drive to each side. Results: Spastic-paretic VEMPs were larger than contralateral VEMPs in 13/16 subjects. There was a strong positive relationship between the degree of asymmetry and the severity of spasticity in this subset of subjects. Remaining subjects had larger contralateral responses. Conclusion: Vestibular drive to cervical motoneurons is asymmetric in spastic stroke survivors, supporting our hypothesis that there is an imbalance in descending vestibular drive to motoneuron pools post-stroke. We speculate this imbalance is a consequence of the unilateral disruption of inhibitory corticobulbar projections to the vestibular nuclei. Significance: This study sheds new light on the underlying mechanisms of post-stroke spasticity.

Original languageEnglish (US)
Pages (from-to)2070-2078
Number of pages9
JournalClinical Neurophysiology
Volume125
Issue number10
DOIs
StatePublished - Oct 1 2014

Keywords

  • Chronic stroke subjects
  • Hemispheric stroke
  • Human
  • Motoneuron
  • Post-stroke spasticity
  • Vestibular evoked myogenic potentials
  • Vestibulospinal

ASJC Scopus subject areas

  • Sensory Systems
  • Neurology
  • Clinical Neurology
  • Physiology (medical)

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